WO1996006349A1 - Detecteur a ionisation de flammes ameliore - Google Patents

Detecteur a ionisation de flammes ameliore Download PDF

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Publication number
WO1996006349A1
WO1996006349A1 PCT/US1995/010895 US9510895W WO9606349A1 WO 1996006349 A1 WO1996006349 A1 WO 1996006349A1 US 9510895 W US9510895 W US 9510895W WO 9606349 A1 WO9606349 A1 WO 9606349A1
Authority
WO
WIPO (PCT)
Prior art keywords
sample
combustion chamber
flame ionization
ionization detector
fuel
Prior art date
Application number
PCT/US1995/010895
Other languages
English (en)
Inventor
Loren T. Mathews
James L. Medici
Original Assignee
California Analytical Instruments, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by California Analytical Instruments, Inc. filed Critical California Analytical Instruments, Inc.
Publication of WO1996006349A1 publication Critical patent/WO1996006349A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
    • G01N30/02—Column chromatography
    • G01N30/62—Detectors specially adapted therefor
    • G01N30/64—Electrical detectors
    • G01N30/68—Flame ionisation detectors
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/62—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode
    • G01N27/626—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode using heat to ionise a gas

Definitions

  • This invention relates to flame analyzing methods and more particularly to an improved detector therefore.
  • FID Flame Ionization Detectors
  • these detectors utilize a mixture of a fuel and the sample gas being tested and ignite the mixture in the presence of polarized electrodes. Ignition of the sample gas causes the molecule being detected to become ionized where upon the electrons are atracted to the positive electrode while the ions are collected on the negative electrode, commonly referred to as the collector. The migration of ions and electrons creates a small ionic current between the electrodes which is related to the quantity of the sought for material in the combustion mixture. Accordingly, as the quantity or the composition of the sample gas changes, a variation in the ionic current can be detected and correlated with the chemical changes.
  • the sensitivity of the FID is also dependent on the potential placed on the electrodes.
  • the collector is operated at a potential of around 180 volts.
  • raising the collector potential will increase the sensitivity of the FID
  • the design of the collector normally limits the operating potential to 180 volts as stated above. Increasing the potential above this point increases the time required to zero the detector between runs. Accordingly it would be desirable to provide an
  • SUBSTITUTE SHEET (RULE 26 inexpensive FID in which the flow rates and pressures of the fuel sample and air gases are closely and continuously controlled in the detector while at the same time providing a design which would allow the detector to be ran at higher collector voltages thus increasing its sensitivity.
  • the device of the present invention is a Flame Ionization Detector (FID) which is rugged, inexpensive to manufacture and relatively easy to maintain.
  • the device utilizes the flame ionization method for the determination of total carbon in a sample gas. In its operation the sample gas is passed through a flame in the presence of polarized electrodes. The migration of the carbon ions to the collector electrode creates a small current which is proportional to the carbon content in the combusted sample gas.
  • the device of the present invention comprises a burner housing which includes a pre-combustion chamber for mixing the fuel and sample gas and a combustion chamber which is in fluid communication with the pre-combustion chamber by means of a burner jet.
  • the combustion chamber is also in fluid communication with a source of hydrocarbon free air which is delivered into the combustion chamber adjacent the burner jet.
  • a collector ring is disposed in the combustion chamber to which a potential is applied for the collection of ions.
  • the collector ring is connected to an electrometer for the read out of the current created by the migration of carbon ions to the collector ring.
  • the collector ring is connected to a power source which imposes a potential on the collector ring and which polarizes the collector ring with respect to the burner jet so that the collector ring and the burner jet function as the polarized electrodes for the FID of the present invention.
  • the sample gas, the fuel gas and the hydrocarbon free air are delivered to the burner housing through critical flow orifices so that the flow rate is uniform and constant throughout the operation of the detector.
  • the detector includes pressure regulators upstream of the critical flow regulators to insure the proper pressure for the sample gas, fuel and hydrocarbon free air.
  • a by-pass flow line communicates with the sample inlet line and opens to the vent. This by-pass flow line improves the response time of the detector.
  • Diagnostic means are provided for monitoring the flow pressures of the sample gas, fuel and hydrocarbon free air as well as the flame temperature in the combustion chamber. Ignition of the fuel air mixture is provided by a conventional ignition device.
  • the provision of a collector ring in the device of the present invention permits higher voltages to be applied to the collector which increases the sensitivity of the device without substantially increasing the time for the detector to return to zero between runs.
  • the critical flow orifices in the inlet lines for the fuel, hydrocarbon free air and the sample eliminate the need for adjustment of the sample, fuel and air gas ratios to optimize the flame by the user of the device.
  • the device of the present invention is easily disassembled and cleaning is a simple operation which can be carried out with relatively little or no operator skill.
  • FIG. 1 is a schematic flow diagram of the device of the present invention
  • FIG. 2 is a side sectional view of the burner assembly of the device of the present invention
  • FIG. 3 is a top sectional view taken along line 3-3 of FIG 2.
  • the device of the present invention comprises a burner assembly 10 to which hydrogen containing fuel gas is introduced through a fuel line 12.
  • a critical flow orifice 14 is disposed in the fuel line 12.
  • a solenoid operated shut off valve 16, a pressure relief valve 18 and a filter 20 are also provided in the line 12.
  • the preferred fuel is a mixture of hydrogen and helium (40% hydrogen/ 60% helium) which is normally maintained in a pressurized container prior to introduction to the burner assembly 10.
  • Valve 18 can be adjusted to allow use of an alternative fuel, such as pure hydrogen.
  • Hydrogen free air is introduced to the burner assembly 10 through an air line 22 and a critical flow orifice 24.
  • the air line also contains a solenoid operated shut off valve 26, a pressure relief valve 28 and a filter 30.
  • a sample gas enters the system through a sample line 32 and critical flow orifice 34.
  • An electronically controlled proportional pressure relief valve 38 and a filter 40 are disposed in the sample line 32.
  • a close coupled by-pass flow line 42 communicates with the sample line 32 for conducting a major portion of the sample gas through a capillary 44 and bypass flow meter 46 to exhaust.
  • a pressure transducer 25 in each of the lines, 12, 22 and 32 senses line pressure and relays a signal to a controller board (not shown).
  • the critical flow orifices, 14, 24 and 34 control respectively the flow rate of the incoming fuel, sample gases and air to produce the optimum flame throughout the life of the detector. Such close control of the flow rates of the incoming gases eliminates the need to optimize each burner to achieve the best conditions for combustion.
  • the flow rate of the sample through the critical flow orifice 24 is small compared to the flow rate of the incoming sample to the critical flow orifice. Consequently at the completion of a run a substantial amount of time is required to bleed the sample through the critical flow orifice so that it may be replaced by a new sample to be tested. This can result in lengthy lag times between runs.
  • This problem is overcome by the provision of the by-pass line 42 and capillary 44 through which a major portion of the sample flows to the exhaust. Accordingly only a small amount of the sample is drawn through the critical flow orifice 34 in the sample line 32 and the time lag necessary to clear the sample line for a new sample gas is substantially reduced.
  • the burner assembly 10 includes a housing 50 which is preferably machined from a solid block of polytetrafluorethylene to have a pair of longitudinally spaced cavities defining a precombustion chamber 54 and a combustion chamber 56.
  • a burner nozzle 60 extends from the precombustion chamber and opens into the combustion chamber 56 adjacent a collector element 70.
  • An exhaust vent 58 communicates with the combustion chamber 56 to carry away the combustion products. The burner vent is open to the atmosphere and, due to complete combustion in the combustion chamber 56 and low associated sample/fuel/air rates, does not require a condensate drain line.
  • the fuel and sample gas mixture are discharged into the cumbustion chamber 56 through the burner nozzle 60 and the air line 22 discharges into the combustion chamber immediatly adjacent the burner nozzle.
  • a glow plug 62 is carried in the wall of the housing for igniting the fuel, air and sample mixture. Power is supplied to the glow plug 62 through a conductor 64 which is in electrical communication with a source of current (not shown).
  • a thermocouple 66 is likewise carried in the housing wall and extends into the combustion chamber 56 for measuring flame temperature. The thermocouple signal is carried to the controller board (not shown) by means of a conductor 68.
  • the collector 70 in the form of a ring or sleeve, is disposed about the inner wall of the combustion chamber 56 and is electrically connected through a line 72 to a power source (not shown) for imposing a potential on the collector.
  • the line 72 also conducts the current created by the flow of ions to the collector 70 during combustion of a sample and is connected to an electrometer of conventional design (not shown) for amplifying the ionization current from the collector.
  • Contact between the collector 70 and the line 72 is provided by electrically conductive spring 73 which compensates for thermal expansion and contraction to maintain electrical contact during operation of the FID.
  • a line 84 also connected to the power source (not shown) provides potential for polarizing the burner nozzle 60.
  • An electrically conductive spring 85 makes electrical contact with the burner nozzle 60 and compensates for thermal expansion and contraction during operation of the FID.
  • the upper portion of the housing 50 is provided with an enlarged collar 80 through which extend bolt holes 82 for securing the burner assembly 10 in a suitable frame or housing (not shown) .
  • the collector 70 is an annular stainless steel member disposed about the inner wall of the combustion chamber 56.
  • a potential applied to the collector 70 and the burner 60 polarizes the collector with respect to the burner nozzle so that the collector and the burner nozzle serve as electrodes for the flame ionization detector of the present invention.
  • the annular configuration of the collector 70 allows for the imposition of collector voltages, on the order of 300v which are high enough to substantially reduce the time required to return the collector to a zero condition after being subjected to high hydrocarbon levels.
  • Conventional flame ionization detectors, which utilize wire as a collector element operate at around 180 volts.
  • the wire collector element of a conventional FID must be properly positioned for optimum performance and is subject to vibration influence and may require re-positioning after shipment.
  • Conventional FIDs utilizing wire collectors are fragile and difficult to clean and it normally requires a skilled technician to dissassemble, clean and reassemble the unit.
  • highly regulated flows of fuel, sample and air are provided to the burner assembly 10 through the critical flow orifaces 14, 24 and 34 respectively.
  • the fuel and air are delivered to the critical flow orifices at 15 psig and consequently the flame characteristics are predetermined without the need of flame optimization adjustments.
  • the sample is introduced to the precombustion chamber 54 through the electronically controlled proportional pressure relief valve 38 and the critical flow orifice 34 in the sample line 32.
  • the by-pass flow line permits flow of the sample gas at between about 2.5 and 4 liters per minute while the sample entering the precombustion chamber 54 through the critical flow orifice 34 flows at the rate of approximately 6 cc/min.
  • the fuel and sample gas are mixed in the precombustion chamber 54 and pass into the combustion chamber 56 through the burner nozzle 60. Carbon free air is lead into the combustion zone adjacent the burner nozzle at a flow rate of about 220mL/min to supply oxygen to sustain combustion.
  • the inlet pressure of the fuel and air are monitored by internal pressure transducers 25 to maintain fuel and air pressure at about 25 ⁇ sig and they act to close the solenoid operated valves, 16 and 26, in the event that there is a loss of fuel or air pressure.
  • the sample gas pressure is maintained at between about 6psig and 25psig.
  • the signal from the thermocouple is monitored at the controller board and in the event of a change in flame temperature from ideal, the solenoid valves 16 and 26 and the pressure relief valve 38 are operated to cut off the flow of fuel, air and sample.
  • the incoming gases in the combustion zone are ignited by the glow plug and the carbon components of the sample undergo ionization that produces electrons and positive ions.
  • a potential of 300 volts is imposed on the collector which serves as the negative electrode of the detector for collecting the ions while the electrons migrate to the burner nozzle.
  • the migration of ions creates a small ionization current which is amplified by the electrometer 78 for processing as a function of the carbon content of the sample.
  • response time is further enhanced by the by-pass line and capillary which permits a major portion of the sample gas to be vented while a minor portion is introduced into the burner assembly 10. This eliminates the presence of excess or dead sample which must be purged before attempting a run on a new sample. Waiting time between sample runs is thus substantially reduced.
  • the solenoid operated valves cut off flow of all of the gases in the event of a drop in pressure or flame temperature which provides the additional benefit of avoiding waste of hydrogen free air as well as the more conventional fuel flow cut off safety feature.
  • the annular collector as contrasted to the conventional wire collectors, provides ruggedness to the burner assembly 10. In addition the burner assembly 10 can be readily cleaned without danger of damaging or destroying the collector.

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  • Chemical & Material Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Other Investigation Or Analysis Of Materials By Electrical Means (AREA)

Abstract

Un détecteur à ionisation de flammes se compose d'un ensemble brûleur (10) qui comprend une chambre de précombustion (54) servant à mélanger le combustible et le gaz d'échantillon, une chambre de combustion (56) pourvue d'un ajutage (60) en communication fluidique avec la chambre de précombustion. Une bague collectrice annulaire (70) et un collecteur d'électrode (73) chargé par ressort, sur lequel est appliqué un potentiel pour la récupération d'ions, sont placés dans la chambre de combustion (56). Le collecteur (70) est raccordé à un électromètre (78) qui amplifie un courant créé par la migration des ions de carbone vers le collecteur (70) lors de la combustion. Des orifices à écoulement critique (14, 24 et 34) placés dans les conduites (12, 22, 32) servent à acheminer le gaz combustible, l'air et le gaz d'échantillon vers le détecteur à ionisation de flammes. La conduite de gaz d'échantillon (32) communique avec une conduite de dérivation (42) et un tube capillaire (44) pour permettre le passage d'une grande partie du gaz d'échantillon directement vers un orifice d'évacuation (58).
PCT/US1995/010895 1994-08-23 1995-08-23 Detecteur a ionisation de flammes ameliore WO1996006349A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US29426994A 1994-08-23 1994-08-23
US08/294,269 1994-08-23

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WO1996006349A1 true WO1996006349A1 (fr) 1996-02-29

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0809109A2 (fr) * 1996-05-25 1997-11-26 Pierburg Aktiengesellschaft Appareil pour la mesure de composants de gaz d'échappement d'une machine à combustion
US6429020B1 (en) * 2000-06-02 2002-08-06 The United States Of America As Represented By The United States Department Of Energy Flashback detection sensor for lean premix fuel nozzles
GB2524853A (en) * 2013-10-11 2015-10-07 Waters Technologies Corp Modulated Flame Gas Flow Rates In Flame-Based Detectors
CN106568888A (zh) * 2016-10-20 2017-04-19 浙江大学 具有稳压功能的测量液体燃料层流燃烧速度的实验装置及其方法
CN109521131A (zh) * 2018-12-04 2019-03-26 杭州谱育科技发展有限公司 色谱检测装置及方法
CN110596291A (zh) * 2019-10-21 2019-12-20 江苏天瑞仪器股份有限公司 一种氢火焰离子化检测器
US10987091B2 (en) 2016-05-17 2021-04-27 Biosense Webster (Israel) Ltd. System and method for catheter connections
CN113465932A (zh) * 2021-06-27 2021-10-01 中国航发沈阳发动机研究所 一种用于加力燃烧室出口总压测量与燃气取样的受感部
CN113984739A (zh) * 2021-09-22 2022-01-28 拓正化工工程(上海)有限公司 基于离子火焰检测系统

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3473895A (en) * 1965-02-09 1969-10-21 Pye Ltd Flame ionisation detectors
US3985509A (en) * 1976-02-13 1976-10-12 Varian Associates Flame ionization detector with flame monitor
US4182740A (en) * 1976-03-01 1980-01-08 Varian Associates, Inc. Flame ionization detector
US4211746A (en) * 1977-04-01 1980-07-08 Wti Wetenschappelijk Technische Instrumentatie B.V. Flame ionization detector
US4341108A (en) * 1979-08-10 1982-07-27 Bayer Aktiengesellschaft Mass flow-dependent gas analyzer with through-flow control during low pressure operation
US4361810A (en) * 1980-05-10 1982-11-30 Ratfisch Instrumente Arrangement for monitoring the concentration of potentially explosive substances in gas streams
US4379402A (en) * 1981-01-22 1983-04-12 Beckman Instruments, Inc. Gas analysis instrument having flow rate compensation
US5073753A (en) * 1987-08-03 1991-12-17 Cambustion, Limited Hydrocarbon flame ionization detector

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3473895A (en) * 1965-02-09 1969-10-21 Pye Ltd Flame ionisation detectors
US3985509A (en) * 1976-02-13 1976-10-12 Varian Associates Flame ionization detector with flame monitor
US4182740A (en) * 1976-03-01 1980-01-08 Varian Associates, Inc. Flame ionization detector
US4211746A (en) * 1977-04-01 1980-07-08 Wti Wetenschappelijk Technische Instrumentatie B.V. Flame ionization detector
US4341108A (en) * 1979-08-10 1982-07-27 Bayer Aktiengesellschaft Mass flow-dependent gas analyzer with through-flow control during low pressure operation
US4361810A (en) * 1980-05-10 1982-11-30 Ratfisch Instrumente Arrangement for monitoring the concentration of potentially explosive substances in gas streams
US4379402A (en) * 1981-01-22 1983-04-12 Beckman Instruments, Inc. Gas analysis instrument having flow rate compensation
US5073753A (en) * 1987-08-03 1991-12-17 Cambustion, Limited Hydrocarbon flame ionization detector

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
SAE HANDBOOK, Volume 3, Published 1991, pages 103-104. *

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0809109A2 (fr) * 1996-05-25 1997-11-26 Pierburg Aktiengesellschaft Appareil pour la mesure de composants de gaz d'échappement d'une machine à combustion
EP0809109A3 (fr) * 1996-05-25 2000-10-04 Pierburg Aktiengesellschaft Appareil pour la mesure de composants de gaz d'échappement d'une machine à combustion
US6429020B1 (en) * 2000-06-02 2002-08-06 The United States Of America As Represented By The United States Department Of Energy Flashback detection sensor for lean premix fuel nozzles
GB2524853A (en) * 2013-10-11 2015-10-07 Waters Technologies Corp Modulated Flame Gas Flow Rates In Flame-Based Detectors
GB2524853B (en) * 2013-10-11 2016-03-30 Waters Technologies Corp Modulated Flame Gas Flow Rates In Flame-Based Detectors
US9625428B2 (en) 2013-10-11 2017-04-18 Waters Technologies Corporation Modulated flame gas flow rates in flame-based detectors
US10987091B2 (en) 2016-05-17 2021-04-27 Biosense Webster (Israel) Ltd. System and method for catheter connections
CN106568888A (zh) * 2016-10-20 2017-04-19 浙江大学 具有稳压功能的测量液体燃料层流燃烧速度的实验装置及其方法
CN109521131A (zh) * 2018-12-04 2019-03-26 杭州谱育科技发展有限公司 色谱检测装置及方法
CN110596291A (zh) * 2019-10-21 2019-12-20 江苏天瑞仪器股份有限公司 一种氢火焰离子化检测器
CN113465932A (zh) * 2021-06-27 2021-10-01 中国航发沈阳发动机研究所 一种用于加力燃烧室出口总压测量与燃气取样的受感部
CN113984739A (zh) * 2021-09-22 2022-01-28 拓正化工工程(上海)有限公司 基于离子火焰检测系统

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